Concentric translating device



April 27, 1954 2,677,079

H. J. M CREARY CONCENTRIC TRANSLATING DEVICE Filed June 11, 1949 3 Sheets-Sheet 1 FROM l SI s as I To PRIOR NEXT 29 3o STAGE T 32 35 34 36 STAGE H H I- I I l l h FIG.3

, IN V EN TOR. HAROLD J. M CREARY ATTORNEY April 7, 1954 H. J. M CREARY CONCENTRIC TRANSLATING DEVICE 3 Sheets-Sheet 2 Filed June 11. 1949 O 0 N 4 3 A Z mw 5o Sago FIG. 4

0.5 L0 INPUT VOLTAGE (V w m. W A m u T l m m m w m m F w so P T U P W o m m w Q SC =E 2220520 2550 m. w A M L om R E W 5P T U P m I! O o w m w m e s 5 $5554? 532 5950 FIG? FIG.6

INVENTOR. HAROLD J. M CREARY Z ATTORNEY April 27, 1954 H J, cc 2,677,079

CONCEN'I'RIC TRANSLATING DEVICE Filed June 11, 1949 3 Sheets-Sheet 3 IN VEN TOR. HAROLD J. M CREARY ATTORNEY Patented Apr. 27, 1954 UNITED STATES ATENT OFFICE CONCENTRIC TRANSLATING DEVICE Application June 11, 1949, Serial No. 98,606

9 Claims.

This invention relates to electrical translating devices and more particularly to those of the solid contact type employing a unidirectional semi-conductive element.

The objects of the invention are to provide a non-thermionic, non-vacuum rectifier and amplifier, and to achieve these ends in a simple and efficient mechanism.

Solid contact detectors have been known and used as rectifying devices for many years, dating bacl; probably as early as 1906. However, their shortcomings were many, including such limitations as the contact with the crystal being broken when the cat whisker was jarred a bit, and even more limiting, the fact that satisfactory amplification of the incoming signal could not be obtained. General usage of this basic detector was more or less abandoned with the introduction and development of the vacuum tube.

The vacuum tube, however, is at best an expensive item to produce, is generally bulky, easily subject to breakage and in ordinary usage requires a heavy supply of current to heat its cathode.

Applicant has overcome these objections by employing unidirectional qualities of certain substances and conceiving the idea that amplification could be had if it were possible to fixedly arrange two conductors minutely spaced apart in contact with a semi-conductor having unidirectional characteristics. Applicant has reduced this principle to practice achieving a translating which perform essentially all the func one of a standard vacuum tube without the incident production costs of a vacuum tube, without appreciable bulk and which requires no filament heating current supply.

A feature of the invention, therefore, is to provide a translating device which is simple in construction and adapted to relatively low cost production methods which will ultimately be reflected in a substantially diminished cost to the consumer.

Another feature of the invention constitutes the close spacing and fixed position of the contact element on a semi-conductor by reason of whi h amplification is achieved.

further feature of the invention lies in the desirability of a translating device which requires no filament heating current.

Still another featur of the invention lies in its adaptability to small size and compact form allowing its use in places heretofore limited because or" space and still further opens a field for smaller overall electronic devices because of the (Cl. EFF-235) diminished size of component translating elements.

Other features will become apparent upon further perusal of the specification and together with the features pointed out will be explained fully hereinafter, reference being had to the accompanying drawings comprising Figs. 1 to 10, inclusive, in which:

Fig. 1 is an axial cross sectional View of the concentric triode translating device;

Fig. 2 is an enlarged cut away axial cross sectional view of the triode depicting the contact relation of the elements thereof with the semiconductiv crystal;

Fig. 3 is an intermediate frequency, I. F., amplifying stage of a standard superheterodyne circuit with the concentric triode in circuit symbol substituted for the amplifier tube;

Fig. 4 is a test circuit for the concentric triode translating device with a potentiometer to vary the resistance in the input circuit and a voltmeter and ammeter in both input and ouput circuit on which to read test data. The meters are labeled A1, V1 and A2 V2, respectively;

Figs. 5, 6 and 7 are graphs of test data obtained by varying the resistance in the circuit in Fig. 4 by means of the potentiometer 31;

Fig. 8 is an axial cross sectional view of the concentric tetrode translator;

Fig. 9 is an enlarged cut away axial cross sectional view of the tetrode depicting the contact relation of the elements thereof with the semiconductive crystal; and

Fig. 10 is a portion of a standard superheterodyne circuit with the concentric tetrode in circuit symbol substituted for the converter tube.

Referring now to Fig. 1 of the drawings for a detailed description of the triode translator structure and its operation, an nvelope defining a cavity therein for housing a semi-conductive crystal element is formed by a hollow cylinder of insulating material 5 which is threaded on its interior at both ends. Into one end of this envelope I is threaded a metal sleeve 2 comprising essentially three steps of increasing diameter, the smallest diameter step or collector 3 extending into envelope l where it terminates in a sharply tapered circular knife edge tip 4, the middle step 5 threaded on its exterior to fit into the end of envelope l described hereinbeiore, and both steps 3 and 5 having a uniform small bore 6 which widens out in the largest step or shank end i into a mouth 8 the interior of which may or may not be threaded depending upon the type of plug to be fitted therein which will be described and whose purpose will be set forth later. A particular embodiment of this sleeve 2 can be a standard #28 hypodermic needle with cannula 3, the part of the shank adjacent the cannula turned down and threaded 5, and a shank l with mouth 8, the cannula sharply tapered to a knife edge tip 4, lumen 6 extending thru cannula 3 and threaded middle step 5, widening into mouth 8 in shank end 1. Into the other end of envelope I is a threaded metal sleeve 9 containing a lateral tapped bore H] for receiving a small set screw II, the purpose for which will also be set out hereinafter. Into sleeve 9 is slidably inserted a short brass rod l2 forming a base electrode, one end of which extends into envelope l and mechanically and electrically fixed to said end of the short brass rod is a semi-conductive element or crystal [3, one embodiment of which may be a standard Sylvania 1N34 type of Germanium crystal. Rearward of said short brass rod I2 with relation to the envelope i in sleeve 9 is slidably inserted a brass control rod [4 one end of which protrudes so that it may be grasped between index finger and thumb and moved in or out as desired. Also within sleeve 9 and between short rod l2 and control rod id is a compression spring l5. Movement inward of control rod it will exert a force on spring 55 which will in turn force short rod l2 forward pressing the semi-conductive element i3 against knife edge tip 6 collector sleeve 3 making solid circula electrical contact therewith. The tip of the knife edge 4 of the cannula 3 may be copper plated and lightly wetted with mercury further to insure crystal l3. Set screw H is then threaded into lateral bore l providing locking means for control rod l4, the circular electrical contact of collector tip 4 with semi-conductive element i3 being fixed and permanent. A fine thinly insulated nickel chrome emitter wire l6 with a ground point tip is fed down the small bore 8 of sleeve 3, wire diameter plus insulation being exactly the size of the bore, until said pointed tip contacts crystal l3. The portion of the emitter wire within the mouth 8 is now coiled into a spring II with the free end l8 passing out of said mouth used as a lead wire for connections.

A plug IQ of an insulating material such as polystyrene or Polythene is provided and shaped to fit mouth 8 by force fit or threaded as desired, plug l9 being center bored a portion of its axial length of a diameter to encase the spring portion I! of emitter wire it, the remaining length center bored of a diameter to permit passage out of free end i8. When the plug 59, encasing the spring I1, is pressed into mouth 8, the pointed tip of emitter wire It is pressed firmly into point contact with crystal l3 and firmly and permanently so held. Said point contact of emitter wire on crystal it will then be permanently held in very close proximity with the circular knife edge contact of tip 4 on crystal I3 concentrically surrounding said emitter point, the distance of separation being at all points the radius of emitter wire 16 plus the thickness of the insulation thereon. At I8, 20 and 2!, leads to the component elements of the triode translating device are indicated. In Fig. 3 is shown a circuit depiction of a standard I. F. amplifying stage in a superheterodyne circuit with a triode transistor substituted for the conventional triode vacuum tube. The I. F. voltage from the previous stage is induced from the primary winding 29 of a transformer to the secondary winding 30 theregood electrical contact with the of. This I. F. frequency is then fed thru the triode translating device hereinbefore described over an input circuit from control electrode or emitter wire I6 thru the tuned input tank circuit comprising condenser 3i and secondary winding 30, battery 32, base electrode !2, and thru crystal I3. Amplification occurs in the output circuit traced from collector 3 thru output tuned tank circuit comprising condenser 33 and primary winding 35 of transformer, and battery 35, base electrode [2 and crystal l3. The amplification gain realized thereby is impressed upon the secondary winding 36 of the transformer to feed into the next stage. The triode translating device may be similarly substituted for a triode vacuum tube in the last or audio-amplifying stage.

In Fig. 4 of the drawings is shown a test circuit having an input and output circuit feeding into and out of the various elements of the concentric triode translating device. The input circuit is traced from the control or emitter wire l6 thru an input ammeter A1, a variable resistance potentiometer 3?, battery 33, base electrode 12 and thru crystal l3. Input voltmeter V1 is bridged across emitter wire it and base electrode 12. Potential for the input circuit is furnished by battery 38. The output circuit is traced from collector element 3 thru output ammeter A2, fixed resistance 39, battery i0, base electrode 12 and thru crystal I3. Again, an output voltmeter, V2, is bridged across collector element 3 and base electrode l2. With the input voltage constant, input current is varied by changing resistance by moving the arm of potentiometer 31. That a gain is achieved in the output circuit is evidenced from perusal of data obtained by reading output meters A2 and V2 and plotting input readings against output readings on graphs in Figs. 5 to '7, inclusive.

In Fig. 5 input voltage V1 in volts is plotted as the abscissa while output voltage V2 is plotted as the ordinate. As the input voltage was decreased from the vicinity of 1.5 volts to approximately .1 volt, the output voltage across base electrode i2 and collector 3 as measured by the voltmeter V2 increased from 20 to 60 volts. Since battery 30 is always of lesser potential than battery 38, this represents an appreciable output voltage increase or gain therein.

In Fig. 6, input power in milliwatts is plotted as abscissa against power consumed by load resistor 39, also in milliwatts. Input voltage remained fixed and as the input resistance is increased by use of potentiometer 3'5, power may be computed by multiplying resistance times the reading of A1 squared times 1000 to obtain results in milliwatts. As the graph shows, at low input power values, from 0-2 milliwatts the output power rose sharply from 550 to the neighbor hood of 650 milliwatts and then tapered off again evidencing power gain across the load resistor.

Fig. '7 again is a graph of data obtained from readings on the meters of the test circuit shown in Fig. 4, plotting power consumed in input air-- cuit in milliwatts against power dissipation of the germanium crystal 13 in the output and input circuits. For an increase in power consumption in the input circuit from 0 to 15 milliwatts, the crystal dissipation in the input circuit increased linearly in the same neighborhood, approximately 15 milliwatts. However, for a small increase of from 0 to 2, milliwatts of power in the input circuit there is a sharp decrease in crystal dissipation in the output circuit from the .5 neighborhood of 150 down to 100 milliwatts, beyond which point the dissipation tapers ofi almost linearly.

Referring again to Figs. 8, 9 and 10 of the accompanying drawings for a detailed description of the structure and operation of the concentric tetrode translator, many elements will be seen to be common to the triode hereinbefore described. Such common or equivalent elements will bear like numbers as this will readily facilitate the description. Therefore, it will be seen that envelope 5, three step sleeve 2 with the exception that bore t of steps 3 and 5 may, but need not be of a larger diameter than in the triode, tip d, shank l, mouth 8, sleeve 9, lateral tapped bore it, set screw ll, short brass rod 12 with semiconductive element i3 mechanically and electrisally attached to one end thereof within envelope 5, control rod id, compression spring 15, emitter wire it, spring portion 17 and free end thereof it, leads 2! and 2!, are of similar construction like function. In addition to these common elements, a third sleeve 22 having on its exterior a fine coating of insulation and its contact end sharply tapered to a circular knife edge tip 23,

inserted in bore 5 of sleeve 2, its tip 23 in contact with crystal it, its other end extending partially up into mouth 8 of shank l, and attached thereto electrically and mechanically as by soldering is a nickel chrome wire 24, the diameter of which need not be as small as emitter wire it, the portion of wire 24 within mouth 8 being coiled into a spring 25 to concentrically envelop Slh'lllg portion il but of sufficiently larger coil diainet r to allow ample space for an insulator tl'ierebetween, the free end 2S of spring 25 continuing on out of mouth 8 and used as a lead wire for connections. The tips of the knife edges i and 23 of the respective elements 3 and 22 may be copper plated and lightly wetted with mercury further to insure good electrical contacts with the crystal l3. Emitter wire it will actually extend down the bore of sleeve 22, which is interposed concentrically between emitter l6 and collector s. In the tetrode, sleeve 22 is comparable to a screen grid for a vacuum tube containing an equal number of elements.

Plug 2?, like plug i9, is made of an insulatin material, such as polystyrene or Polythene, and shaped to fit mouth 3 either by force fit or threaded, and is center bored a. portion of its axial length of sufiicient diameter to accept spring portion ll of emitter It, the remainder center bored of sufficient diameter to permit passage out of free end 58. Plug 2'! then has a sec- 0nd cavity therein concentric with the larger diameter center bore, of sufficient size to accept spring portion 25 of wire 24, with an insulating wall between spring H and spring 25, said wall being integral with the remainder of the plug. Plug 21 also has another small bore 01f center communicating with said concentric cavity to errnit passage out of the free end 26 of wire 2 And finally a seal 28 such as Wax, cellulose cement or the like is placed over the external end of the plug and free end leads l8 and 26, to completely render the translator moisture and atphere proof. t 9 is merely an enlarged cut away view showing in greater detail the manner in which th concentric sleeves are insulated one from another, how the ends are tapered to circular knife edges and the way in which said knife edges make concentric contacts with the crystal element l3.

In Fig. 10 is depicted a concentric tetrode transistor in the converter stage of a superheterodyne circuit, the tetrode transistor having been substituted for a conventional four element vacuum tube. In the circuit as shown a signal of a radio frequency is received on antenna l and induced into the secondary winding of antenna coil 42. The R. F. signal from the antenna so induced is tuned by condenser 43 so that a maximum R. F. potential is applied between base electrode i2 and sleeve 22. Local oscillation is tuned by condenser M which is ganged conventionally to condenser 83 and this local tank circuit comprising condenser 44 and transformer winding is connected across emitter wire [5 and base electrode [2. The input circuit of the mixer stage is traced from crystal [3 thru collector sleeve 22, tank circuit comprising winding 32 and condenser #3, battery 4? to base electrode it. The output circuit of this mixer stage is traced from crystal !3 thru collector 3, transformer winding 46, tank circuit comprising condenser 49 and winding 50, battery 48 to base electrode 12. A feed back circuit is established from current induced from winding 46 of output circuit back onto winding and its associated tank circuit including condenser 4 3 and thru coil 32 to feed sleeve 22. Local oscillation set up by the local tank circuit beats against the R. F. fed into the tetrode transistor via the input circuit resulting in an intermediate frequency I. F. in the output circuit which is induced onto coil 5i and passed to a subsequent stage such as described hereinbefore in regard to a triode transistor in an I, F. amplifying stage of such a conventional superheterodyne circuit.

From this detailed description of the triode and tetrode translating devices described herein it can readily be appreciated that transistors of any increased order of elements can be made by merely adding the desired number of insulated concentric sleeves between emitter and collector and increasing the number of concentric springs and cavities to house the spring portions of the elements commensurately. The applicant therefore does not limit his disclosure to translating devices of the order of triodes and tetrodes but expresses inclusion of all higher orders of elements limiting such number only by the bounds of practicality.

Upon disclosure what is claimed and what applicant desires to be protected by issuance of Letters Patent thereon is:

1. In a translating device of the character described; an envelope of insulating material, two metal sleeves communicating with the interior of said insulating envelope from both ends; the first sleeve comprising three steps of increasing diameters, the middle step fitting tightly into one end of said insulating envelope, the smallest step continuing into said envelope, the smaller two steps having a relatively small bore of uniform diameter, said bore widening out in the third step into a divergent walled mouth; the second sleeve having a uniform bore thruout its length, and fitting snugly into the other end of said insulating envelope, a short rod positioned slidably in second sleeve and extending into said envelope, semi-conductive crystal affixecl to and electrically connected with the end of said short rod within said envelope, an adaptable control rod also fitted into said second sleeve behind said short rod with relation to said envelope, means to lock said control rod, and a compression spring between said two rods; said rods, locking means and spring cooperating to hold said crystal in circular electrical contact with the smallest diameter end of said first sleeve; an insulated emitter wire extending down the small bore of said first sleeve and terminating in a ground point end, said wire being coiled into a spring toward its other end, and a plug of insulating material shaped to snugly fit said divergent walled mouth, said plug, when fitted into said divergent walled mouth exerting a force on said coil portion of the emitter Wire firmly holding said pointed end thereof in electrical contact with said crystal, said point of contact being equidistant from all points of contact on the circular sleeve contacting surface surrounding said point.

2. In a translating device of the character described; an envelope of insulating material threaded at both ends, two metal sleeves communicating with the interior of said insulating envelope from both ends thereof; the first sleeve comprising a metallic hypodermic needle, the exterior of the shank end of said needle being threaded to fit into the end of said insulating envelope, the cannula of said needle being cut off perpendicularly to the axis thereof at a point allowing said cannula to extend into said envelope major portion of its length; the second sleeve having a uniform bore thruout its length and threaded into the other end of said envelope, a short rod positioned slidably in said second sleeve and extending into said envelope, a semi-conductive crystal aflixed to and in electrical connection with said rod within said envelope; and means including a compression spring for holding said crystal in firm circular electrical contact with the cut off end of said cannula; an emitter wire extending down the lumen of said cannula, terminating in a ground point against said crystal, said emitter being coiled into a spring towards its other end; a plug of insulating material shaped to snugly fit the mouth of said needle; said plug being partially bored to retain said coiled spring end of the emitter wire; said plug when fitted into said mouth exerting a force on said coil portion of the emitter firmly holding said ground point end in electrical contact with said crystal, insulating means maintaining said point of contact of said emitter with said crystal equidistant from all points of contact of the cannula with said crystal so that a weak signal incoming on said emitter wire will excite a field in said crystal about said emitter contact point, excitation of said crystal occurring equally in all directions at once, said signal translated onto said continuous circular cannula contact surface within said field and conducted away thereon in a rectified and greatly amplified form.

In a translating device substantially as described in claim 2, a copper plated tip on said cannula, the surface of said cannula tip lightly wetted with mercury to insure complete electrical contact of said cannula with said semi-conductive crystal.

2. In a translating device sultistantiall as de scribed in claim 2, said semi-conductive crystal being composed substantially of the element germanium.

5. In a translating device, a semi-conductive crystal, an emitter wire in point contact with said crystal, insulation coated on said emitter wire, a co-axial cylindrical collector concentrically surrounding said emitter and insulated and separated therefrom only by the thickness or said insulation, a coat of insulation on the exterior of said collector, and another co-axial cylindrical collector concentrically surrounding said former collector and insulated and separated therefrom by said coat of insulation therebetween; said collectors being in concentric circular contact with said crystal around said emitter contact point; circuits associated respectively with said crystal, emitter and each collector; the close relationship of the three contacts on said crystal being such that a small signal incoming on said emitter and exciting said crystal causes ionization to occur in all directions simultaneously, said signal being translated and given increased impetus thru said crystal by the inner collector and collected and sent out on the outer collector in greatly amplified form, said inner collector being positioned to eliminate capacitative feed back between said outer collector and said emitter.

6. In a translating device of the character described, an envelope of insulating material, two coaxial metal sleeves communicating with the interior of said envelope from both ends; the first sleeve fitting tightly into one end of said insulating envelope, an extension of said first sleeve continuing into said envelope, the second sleeve having a relatively medium bore uniform thruout its length and fitting snugly into the other end of said envelope, a short rod positioned slidably in said second sleeve and extending into said envelope, a semi-conductive crystal afiixed to and electrically connected with the end of said short rod within said envelope, an adjustable control rod also fitted into said second sleeve behind said short rod with relation to said envelope and a compression spring therebetween, means to lock said control rod; said rods, spring and locking means co-operating to hold said crystal in firm circular electrical contact with the small diameter of said extension on said first sleeve; a third sleeve concentrically secured with in said first sleeve, an exterior coating or" insulation on said third sleeve insulating and separating said third. sleeve from said first sleeve by the thickness of said coating of insulation; an emitter wire extending down the bore of said third sleeve, said emitter wire having a coat of insulation insulating and separating said wire from said third sleeve by the thickness of said coat of insulation on said wire, a ground point terminating said emitter wire at one end and said emitter wire being coiled into a spring towards its other end; another wire joined to said third sleeve within the mouth or" said third sleeve and being coiled to form a spring concentric with the spring portion of said emitter wire but of larger diameter, and a plug of insulating material threaded to fit the mouth of said first sleeve, said plug having a partial center bore of a diameter sufdcient to encase the coiled spring portion of said emitter wire, said plug having a second cut out cavity concentric with the partial center bored portion to encase said coiled spring portion of the wire attached to said third sleeve, said cavity being separated from said center bored cavity by a cylindrical wall integral with the remainder of said plug, said plug when threaded into said threaded mouth exerting a force on said coiled portions of said wires firmly holding said pointed end of said emitter wire, and the end of said third sleeve within said envelope in electrical contact with said crystal.

'7. In a translating device of the character described, an envelope of insulating material threaded at both ends, two co-axial metal sleeves communicating with the interior of said envelope from both ends thereof; the first sleeve comprising a metallic hypodermic needle, the exterior of the shank end of said needle being turned down and threaded, fitting into one end of said envelope by said threads, the cannula of said needle being cut off by tapering sharply to a circular knife edge, at a length allowing said cannula to extend into said envelope a major portion of the latters length; the second sleeve having a uniform bore thruout its length and threaded into the other end of said envelope, a short rod positioned slidably in said second sleeve and one end extending into said envelope, a semi-conductive crystal affixed to and electrically connected with the end of said short rod within said envelope, an adjustable control rod also fitted into said second sleeve behind said short rod with relation to said envelope and a compression spring therebetween, means to lock said control rod; said rods, spring and locking means co-operating to hold sai-i. crystal in firm circular electrical contact with the knife edge tapered tip of said cannula; a third sleeve concentrically secured within the lumen of said cannula and having one end sharply tapered to a circular knifelike edge and engaging said crystal and the other end extending up into the mouth of the needle within the shank end thereof, insulation on said third sleeve insulating and separating said third sleeve from said cannula by the thickness of said insulation; an emitter wire extending down the bore of said third sleeve, insulation on said emitter wire insulating and separating said Wire from said third sleeve by the thickness of said insulation thereon, said emitter wire terminating in a ground point at one end, said emitr.

ter wire being coiled into a spring towards its other end; another wire joined to said third sleeve within the mouth of said shank and coiled to form a spring concentrically enveloping the spring portion of said emitter wire; and a plug of insulating material threaded to fit the mouth of said shank, said plug having a partial center bore of a diameter sufiicient to cheese the coiled spring portion of said emitter wire and said plug having a second cut out cavity concentric with the partial center bored portion to encase said coiled spring portion of said second wire attached to said third sleeve, said cavity being separated from said partial center bored portion by a cylindrical wall integral with the remainder of said plug, said plug when threaded into said mouth in said shank exerting a force on said coiled portions of said wires firmly hold ing the pointed end of said emitter wire and the circular knife edged end of said third sleeve in electrical contact with said crystal.

8. In a translating device substantially as described in claim 7, a copper plated tip on said sharply tapered knife edge ends of said cannula and said third sleeve, the circular knife edges of said copper plated tips being lightly Wetted with mercury to insure complete electrical contact of said concentric knife edge contacts with said. semi-conductive crystal.

9. In a translating device substantially as described in claim 7, said semi-conductive crystal being composed substantially of the element germanium.

References Cited in the file of this patent UNITED STATES PATENTS 

